Recent years have seen a huge increase in the number of children born via IVF and other fertility treatments (in 2011 in the UK, 17,041 babies were born via IVF). While this has undoubtedly brought immeasurable happiness to many families, medical experts have raised concerns that the steps involved in IVF – such as the direct implantation of embryos into the mother’s uterus, and in some cases the injection of an individual sperm cell into the egg – may bypass some biological filtering processes thereby increasing the odds of inherited illnesses and disorders.

The existing research literature looking into this issue is incredibly contradictory. For example, some studies have found evidence of a higher prevalence of cognitive and social problems in children born through fertility treatments, yet other studies have found nodifferences between children born by IVF and their peers, while still other studies have actually documented advantages in IVF children. Part of the reason for the mixed results may be to do with the different cognitive and social measures used and changes to fertility treatment procedures over the years.

To this field comes a new paper in the European Journal of Developmental Psychology. The researchers led by Edwa Friedlander at the Hebrew University of Jerusalem hoped to improve upon the existing evidence base by using three gold standard measures of cognitive and social development, and by focusing on children born with the help of IVF (and the ICSI variant involving individual sperm injection).

The researchers compared 67 children born with the help of IVF and 67 children born without any medical intervention. At the time of assessment, the children in each group had an average age of four, with a range between 1 year 11 months and 7 years 6 months. Using the researcher-administered “Mullen scales of early learning” that taps motor control and language, and the researcher-administered “Autism Diagnostics Observation Schedule” which measures autistic-like behaviours and symptoms, the researchers found no differences between the two groups. Meanwhile, using the Vineland – a structured interview that involves asking parents or caregivers questions about the child’s social, communication and motor skills – the researchers actually found the IVF group’s scores on communication and motor skills were superior compared with their peers.

Friedlander and her colleagues concluded that infertile couples and medical professionals who work in the field of fertility treatments “can be encouraged by the current findings”. However, they do add several notes of caution. For one thing, the assessments used in the current study are not sensitive enough to detect some specific signs and symptoms associated with developmental conditions, and also some potential deficits may not appear until later in childhood.

Another thing: the apparent advantage for the IVF group was only seen in the parental interviews, which of course involved a large degree of subjectivity. It’s worth bearing in mind that other research has similarly documented advantages for IVF children as measured by parental report, but not through researcher-administered tests. That said, another recent study using a clinician-administered test did report motor development advantages for IVF-conceived children. There’s definitely a need for more research to iron out these contradictory findings, but if the developmental advantages for IVF-conceived children do turn out to be real, this would raise some very interesting questions about why they exist – for example, might the parenting styles of IVF parents play a part?